4D Printing of Extrudable and Degradable Poly(Ethylene Glycol) Microgel Scaffolds for Multidimensional Cell Culture. Issue 36 (22nd June 2022) - Miksch, Connor E.
Abstract: Granular synthetic hydrogels are useful bioinks for their compatibility with a variety of chemistries, affording printable, stimuli‐responsive scaffolds with programmable structure and function. Additive manufacturing of microscale hydrogels, or microgels, allows for the fabrication of large cellularized constructs with percolating interstitial space, providing a platform for tissue engineering at length scales that are inaccessible by bulk encapsulation where transport of media and other biological factors are limited by scaffold density. Herein, synthetic microgels with varying degrees of degradability are prepared with diameters on the order of hundreds of microns by submerged electrospray and UV photopolymerization. Porous microgel scaffolds are assembled by particle jamming and extrusion printing, and semi‐orthogonal chemical cues are utilized to tune the void fraction in printed scaffolds in a logic‐gated manner. Scaffolds with different void fractions are easily cellularized post printing and microgels can be directly annealed into cell‐laden structures. Finally, high‐throughput direct encapsulation of cells within printable microgels is demonstrated, enabling large‐scale 3D culture in a macroporous biomaterial. This approach provides unprecedented spatiotemporal control over the properties of printed microporous annealed particle scaffolds for 2.5D and 3D tissue culture. Abstract : Microgel scaffolds are prepared from chemically modular synthetic polymer precursors, allowing for post‐printing tuning of void fraction, logic‐gated degradation, and bioprinting of cells encapsulated in 2.5D and 3D culture. Cellularized microgel constructs enable high viability on length scales that are inaccessible by bulk encapsulation, presenting opportunities for additive manufacturing of large format cell‐laden biomaterials for tissue engineering and regenerative medicine.